A human liver cell measures 20 `mum` in diameter. This is equivalent to :

Options

A. 200 nm
B. 0.02 nm
C. 0.02 `mum`
D. 2000 nm

Explanation

To convert the diameter of a human liver cell from micrometers to nanometers, follow these steps:

### Step-by-Step Solution:

1. **Understand the Units**:
- The question states that the diameter of a human liver cell is 20 micrometers (µm).
- We need to convert this measurement into nanometers (nm).

2. **Conversion Factors**:
- Recall that 1 micrometer (µm) is equal to \(10^{-6}\) meters.
- Recall that 1 nanometer (nm) is equal to \(10^{-9}\) meters.

3. **Convert Micrometers to Meters**:
- Convert 20 micrometers to meters:
\[ 20 \, \mu m = 20 \times 10^{-6} \, m = 2 \times 10^{-5} \, m \]

4. **Convert Meters to Nanometers**:
- Since 1 nanometer is \(10^{-9}\) meters, we can convert meters to nanometers:
\[ 2 \times 10^{-5} \, m = 2 \times 10^{-5} \, m \times \frac{1 \, nm}{10^{-9} \, m} = 2 \times 10^{-5} \times 10^{9} \, nm = 2 \times 10^{4} \, nm = 20,000 \, nm \]

5. **Final Answer**:
- Therefore, the diameter of the human liver cell in nanometers is 20,000 nm.

### Conclusion:
The diameter of a human liver cell measuring 20 micrometers is equivalent to **20,000 nanometers**.

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